1. Field of the Invention
The present invention relates to LED display devices and, more particularly, to an image display device with a structure in which a plurality of display units, each comprised of a display panel, are arrayed in a vertical or lateral direction to provide an image in an enlarged scale, and an improvement over a unit connecting mechanism suited for connecting the plural display units to form the image display device.
2. Description of the Related Art
Image display devices of a large screen each including a display panel composed of a large number of display elements, such as LEDs (Light Emitting Diodes), which are disposed in a matrix form are mounted on outer walls (building boards) of buildings located in indoor or outdoor gymnasiums, a variety of event sites or business quarters. These image display devices are structured to be operative to provide displays of advertisements or guidance, or displays of television images using controls of turning on or turning off “R” (Red), “G” (Green) and “B” (Blue) to provide so-called full color displays.
In state-of-the-art, it has been a usual practice to structure the image display device of such a large screen with the use of large number of flat box-like units, each including a plurality of preliminarily assembled display panels, which are connected in a vertical and lateral direction to form an assembled structure, which in turn is mounted to a structure such as a building to be fixedly used at such a site for a long period of terms or to a bed of a large size vehicle to be used in a mobile form.
Since the image display device of the related art includes the large number of display units arrayed in the vertical and lateral direction in a connected relationship, there are many instances in which the display device is usually carried to an installation site in a form of disassembled display units, which are then assembled into a final structure at that site to be used and, after the use of the image display device has been terminated, the image display device is disassembled again into the individual display units which are in turn carried to another event site.
FIGS. 1 and 2 show outer appearances of the image display device of the related art stated above, with FIG. 1 being a partially exploded view of a box-like unit 1 and FIG. 2 being a perspective view of the display unit as viewed from a rear side.
The box-like unit 1 is comprised of a front panel 12, having a plurality (shown in six pieces in FIGS. 1 and 2) of display panels 11 formed in rows and columns, which is fixed to a rear panel 14 by means of a plurality of struts. Each display panel 11 includes a large number of display elements 11a, such as LEDs, which are regularly arrayed in a matrix form. An auxiliary strut 13a, that also serves as a reinforcing member, extends between the right and left struts 13, 13 at intermediate areas thereof and is fixed thereto.
Further, fitted below the lower most struts 13, 13 and between the front panel 12 and the rear panel 14 are leg members 15, 15 that play roles as interconnecting members to enable other display units 1 to be coupled.
As shown in FIG. 2, the rear panel 14 is comprised of a chassis 141 and an openable door 142 mounted to the chassis 141, with a control unit 16 for controlling the display elements 11a being mounted to an inner side of the door 142.
As shown in cross section in FIG. 3, the strut 13 has a structure shaped in a rectangular configuration with cavity portions 131 formed at four corners. Also, FIG. 3 shows a situation in which the strut 13 is connected to the leg member 15.
As shown in FIGS. 1 and 2, further, the strut 13, the auxiliary strut 13a and the leg member 15 are formed with connecting members 2, respectively, that serve as interconnecting members to allow the other box-like units 1 to be coupled in the vertical and lateral direction.
The connecting member 2 is comprised of a movable segment 21 and an engagement segment 22 which are located in a pair, with a so-called unit connecting mechanism having a connecting capability of interconnecting adjacent box-like units 1 to be disposed in the vertical and lateral direction. As shown in FIGS. 1 and 2, one of the box-like units 1 to be interconnected is formed with either the movable segment 21 or the engagement segment 22 to allow the one display unit 1 to be connected to or disconnected from the other box-like unit 1.
FIG. 4 is an enlarged right side view of an essential part under a condition in which upper and lower box-like units 1, 1 are connected to one another with the connecting member 2 employing a so-called twisting operation mechanism. The strut 13 of the lower box-like unit 1 is mounted with the movable segment 21, and the leg member 15 of the upper box-like unit 1 is mounted with the engagement segment 22, with engagement operation of these segments compelling the upper and lower display units to be coupled to one another.
Now, the operation of coupling and uncoupling of the connecting member 2 is described below with reference to FIGS. 5A and 5B which are views as viewed in an arrow V-V in FIG. 4. As shown in FIG. 5A, the connecting member 2 is structured such that rotating a grip 211 of the movable member 21 in a direction as shown by an arrow R causes a hook portion 212 to protrude or retract in a direction as shown by an arrow Y.
Thus, as shown in FIG. 5B, rotating the grip 211 of the movable segment 21, remaining in a closed position, in the direction as shown by the arrow R causes the hook portion 212 to be lowered in a direction as shown by an arrow Y1 to capture and pull an annular engagement segment 22 of the upper display unit 1, rendering the upper and lower box-like units 1, 1 to be brought into a coupled condition.
Also, the grip 211 of the movable segment 21 has a structure that can be folded with the engagement segment 22 held in a pulled condition. For this reason, as shown in FIG. 4, the connecting member 2 is brought into locked condition. Also, the connecting member 2 is brought into an uncoupled condition by moving the grip 211 in a reverse direction.
Although the upper and lower box-like units 1, 1 have been described above to form an assembled structure, the right and left box-like units 1, 1 may also be coupled to one another via the connecting member 2 in the same manner as set forth above. As shown in FIGS. 1 and 2, the connecting member 2 disposed between the lateral right and left box-like units 1, 1 has the same structure as that of the connecting member 2 disposed between the upper and lower box-like units 1, 1. Using the connecting members 2 in the vertical direction and the lateral direction enables the plural box-like units 1, 1 to be coupled into an assembled structure in an expanded condition in the vertical and lateral direction as viewed in FIG. 6.
Also, in order to couple the plural box-like units 1, 1 to one another, there are some instances in which through holes are formed in the respective struts 13, 13 to allow bolts to be inserted through the through holes of the struts 13, 13 of the respective box-like units 1, 1 to cause the bolts to be tightened without relaying on the coupling or uncoupling operations of the connecting members 2, 2 extending between the adjacent box-like units 1, 1.
With the image display device of such a related art set forth above, attempts have been made to cause the connecting member to extend between respective struts, the auxiliary struts or the leg members of the adjacent display units to be fixedly mounted, or other attempts have been made to fixedly couple the struts pre se of the adjacent display units by means of fixture bolts.